Posted 23 May 1997
What's the worth of the Earth? According to Robert Costanza of the University of Maryland it's about $33 trillion.

That, at least, is the average annual value of "natural capital" and the services provided by the world's ecosystems, says Costanza whose calculations were published in the May 15 issue of the journal Nature.

Some Freebies From Nature
Breathable Air
Potable Water
Waste Assimilation
Natural Pollination
Food Production
Flood Control
Soil Production
Genetic Raw Material
Timber Production

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This astonishing figure, almost twice the global gross national product of $18 trillion, takes on added significance this week as representatives from 150 nations meet in Kyoto, Japan, in an effort to come to economic terms with global climate change. It was arrived at by calculating the economic value of a set of ecosystem services -- the production of breathable air, potable water and food, and the assimilation of wastes -- across a range of ecosystems, from forests and oceans to lakes and mountains.

Costanza's study joins a growing movement by scientists who are attempting to formulate the "market value" of the things the world gives us for free. It's a slippery issue, they acknowledge, but we are utterly dependent on these services and the attempt to price them will help ensure that environmental services are given greater consideration in policy debates.

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The price of air just went up...
"There are all sorts of things we take for granted that are supplied to us easily by nature," says Paul R. Ehrlich, an ecologist at Stanford University. "But these services are being degraded over the entire planet."

If we are to make any progress toward solving environmental problems, there needs to be a better way to factor in natural services that we depend on, says Geoffrey Heal, a professor of business at Columbia University.

"An ecosystem is a capital service. It provides a flow of services" worth trillions of dollars every year, says Heal.

While the sure-to-be-stormy summit in Kyoto focuses on climate and the economic costs involved with mitigating human influences on it, it may serve delegates and world leaders to factor in the costs of things we've always taken for granted.

The latest study, according to Costanza and his co-authors, is not meant to be definitive. Their aim, they say, is twofold: to couch the value of ecosystem services in terms policy makers like those meeting in Kyoto can understand, and to stimulate debate, perhaps the study's only sure outcome.